Three stories of people who’ve made surprising discoveries in their own family trees.

Though our physical characteristics vary widely, humans in general share 99.9 percent of the same DNA. It's the .1 percent that gives us our differences. And thanks to recent advancements in DNA science, people can now discover potentially life-changing information by simply mailing off a saliva sample for testing.

What can ancestral DNA testing tell you about your family history? Below, explore three stories of people who’ve made surprising discoveries in their own family trees.

Prince William, second in line to the British throne, was surprised to learn he likely possesses Indian heritage passed down through the family of his mother Princess Diana. He traced the lineage back to his great-great-great-great-great grandmother Eliza Newark. Though she was described in records as Armenian, her mitochondrial DNA is tied to populations from the Indian subcontinent.

The family of Albert Perry, a recently deceased African-American man from South Carolina, sent his DNA to the National Geographic Genographic Project. The results were surprising—Perry carried a Y-chromosome that could be traced back 338,000 years to central Africa. Y-chromosomes are passed down directly from fathers to sons and only change through gradual mutation. The DNA test gave Perry's family a direct genetic connection to the "Y-chromosomal Adam."

Many people take tests in hopes of being connected to some famous ancestor. Al Jazeera contributor Lindsay Moran wrote an article in which she admitted that part of her motivation for taking a DNA test was to find out whether or not she was descended from the last Russian Tsar (a fantasy fed by the knowledge that her mother's family hailed from Russia). It turns out she wasn't, but that she probably does share an ancestor somewhere in history with celebrity chef Mario Batali.